| 摘要 |
PURPOSE:To prevent beat failure, by taking the frequency dividing ratio of a prescaler to a specific value. CONSTITUTION:The range of harmonics where beat failure can normally be suppressed is that the harmonics are apart from a reception frequency by + or -300kHz or more. This is because the characteristics of a filter used for a radio receiver have a band of about 300kHz. Thus, no beat failure takes place when the relation of Equations (1), (2) is satisfied in case of FM broadcast in Japen, where the 1/p is the frequency dividing ratio of a prescaler, (k) is the number of order of harmonics, fs is the reception frequency, fi(=10.7MHz) is the intermediate frequency, alpha is the difference between the reception frequency fs and the harmonics (=300kHz). Thus, in seeking the frequency dividing ratio satisfying the relation, p=16.17 can be obtained. |
